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July 18, 2004
G'day Nigel et al
As much as I agree with Bob (get a new one) I understand your penchant for originality and budget repairs. So here is an (almost) fail-safe method for freeing seized hydraulic components.
(No, Nigel, I'm not being a smart-ass - we all have times where we just have to repair the used bit in front of us.)
Take the part in question, let's say it's a clutch slave cylinder, remove all pipes and hoses, clean all the rust and debris out of the cylinder in front of the piston. You need to make it as easy as possible for the piston to come out once it is free. We usually just rub it with emery paper and then hone the cylinder as far down as we can get to the seized piston.
Then, through (say) the bleed niple hole, fill it with WD40 or some other thin lubricant. NOT petrol, kerosine etc that are highly flammable. You can use water if you have to. Block all holes (in this case, the bleed hole and the hole for the fluid line) with bleed nipples.
Hold the cylinder in a vice with the piston pointing at nothing fragile (including you) and gently heat it. Oxy-acetylene on a soft flame is great, but if you don't have oxy gear a butane torch will work. Move the heat all around the cylinder so you don't get localised hot spots.
The fluid inside the cylinder will expand and force the piston out. Sometimes it will come out like a bullet. I usually stick a cardboard box or two in front of the piston to catch it, but I have on occasions blown holes right through the box.
Be afraid, be very afraid. When it does come free, it will scare the s#!t out of you.
I have used this method sucessfully on clutch slave cylinders, master cylinders, brake wheel cylinders and disc brake calipers. We managed to remove the two pistons from an AC Aceca one-piece disc caliper that had been sitting for 40 years and was rusted solid.
avagoodday
Colin
"Colin@SpriteParts" < colin@... > 33057
Posted on July 18, 2004 08:55 AM
Posted to category(s) Braking System | Cooling System | Drive Train | Engine (external) | Engine (internal) | Exhaust System | Intake System | Lubrication System | Restoration | Transmission | US States | Wheels
